Schools have been told they should be doing more to help underperforming children struggling with maths.

About 50 per cent of primary schools could improve their pupils' maths results if they used assessment data to adapt the curriculum to meet their needs, an Education Review Office report issued yesterday says.

Most schools are good at identifying students who need more help, it says, but many continue using the same teaching tools that had already proved ineffective.

Clyde Quay School principal Liz Patara said not all schools used outdated tools. A common maths intervention programme used in primary schools was called Spring.

"When the Spring programme is used, students still end up getting a double dose of learning because their teacher will also use different resources to help the children grasp different concepts."

The ERO report says that, in at least half of schools, it is teacher aides who work with underperforming pupils, rather than experienced teachers.

Ms Parata said that was because funding did not allow for more teachers, and schools could only work with what they were given.

"We're dealing with high-needs children, a growing population and a number of students where English is their second or even third language, and making something fit for everyone is a real challenge."

Victoria University curriculum senior lecturer Robin Averill said parents should not panic about the report because its purpose was to provide useful tools to help schools. "The report has homed in on the national standards tool and how teachers are using that to assess students."

The reality was that most schools were using a range of tools and assessments to measure pupils' performance.

Khandallah Primary School principal Louise Green said the report summed up exactly why national standards did not work, and the negative impact on children's learning.

"Teachers have been concerned for some time that . . . testing and measuring required by national standards would result in inflexibility in the curriculum. Now we have some proof."

The ERO report's findings are based on reviews of 240 primary schools and focus on the maths achievements of pupils in years 4 to 8.